The opening and closing of contacts within electrical switching equipment has traditionally been done through the use of mechanical switches in electrical components such as circuit breakers, contactors, motor starters, motor controllers and other load controllers. Exemplar switches are disclosed in U.S. Pat. No. 5,856,643, U.S. Pat. No. 4,176,262, and U.S. Pat. No. 4,743,876 and are incorporated herein by reference. Circuit breakers contain separable primary contacts as well as an MOC operator that controls the MOC assembly. In particular, control of the MOC assembly has traditionally been accomplished through mechanical means, and has utilized an interface mechanism such as a pantograph assembly and an MOC operator on the circuit breaker. As originally designed, the MOC operator engages and applies a generally downward force when the circuit breaker closes and upward force when the circuit breaker opens on the MOC assembly. The application of these forces on the MOC assembly causes an MOC rod connected to the MOC assembly to move in corresponding directions and thereby change the status of the MOC assembly.
Due to the various designs employed by various electrical equipment manufacturers, replacement of electrical components such as vacuum circuit breakers which utilize the MOC assembly is often difficult. In particular, pantograph coupling or engagement to the MOC operator is often a dynamic mismatch. The force applied by a new MOC operator to the existing MOC assembly is often significantly higher than that originally designed—in some instances as large as 16 times the force applied by the original MOC operator. Under such circumstances, premature wear, or failure of the MOC assembly is likely. Moreover, the excessive force on the MOC assembly may cause significant contact bounce. Also, the force requirements placed on the circuit breaker can cause stalling of the circuit breaker. Accordingly, there is a need for a method and apparatus for controlling the forces applied to the MOC assembly and which may be readily used and applied to the myriad of brands and types of electrical switching equipment.